--- a/layout/reftests/image/reftest.list
+++ b/layout/reftests/image/reftest.list
@@ -40,29 +40,29 @@ fuzzy(1,1) == image-orientation-explicit
 fuzzy(1,1) == image-orientation-explicit.html?270      image-orientation-ref.html?270
 fuzzy(1,1) == image-orientation-explicit.html?0&flip   image-orientation-ref.html?0&flip
 fuzzy(1,1) == image-orientation-explicit.html?90&flip  image-orientation-ref.html?90&flip
 fuzzy(1,1) == image-orientation-explicit.html?180&flip image-orientation-ref.html?180&flip
 fuzzy(1,1) == image-orientation-explicit.html?270&flip image-orientation-ref.html?270&flip
 
 # Tests for image-orientation used with non-axis-aligned angles:
 fuzzy(1,1) == image-orientation-explicit.html?-46      image-orientation-ref.html?270
-fuzzy(1,1) fails-if(styloVsGecko||stylo) == image-orientation-explicit.html?-45      image-orientation-ref.html?0
+fuzzy(1,1) == image-orientation-explicit.html?-45      image-orientation-ref.html?0
 fuzzy(1,1) == image-orientation-explicit.html?-15      image-orientation-ref.html?0
 fuzzy(1,1) == image-orientation-explicit.html?15       image-orientation-ref.html?0
 fuzzy(1,1) == image-orientation-explicit.html?45       image-orientation-ref.html?90
 fuzzy(1,1) == image-orientation-explicit.html?75       image-orientation-ref.html?90
 fuzzy(1,1) == image-orientation-explicit.html?105      image-orientation-ref.html?90
 fuzzy(1,1) == image-orientation-explicit.html?135      image-orientation-ref.html?180
 fuzzy(1,1) == image-orientation-explicit.html?165      image-orientation-ref.html?180
 fuzzy(1,1) == image-orientation-explicit.html?195      image-orientation-ref.html?180
 fuzzy(1,1) == image-orientation-explicit.html?225      image-orientation-ref.html?270
 fuzzy(1,1) == image-orientation-explicit.html?255      image-orientation-ref.html?270
 fuzzy(1,1) == image-orientation-explicit.html?285      image-orientation-ref.html?270
-fuzzy(1,1) fails-if(styloVsGecko||stylo) == image-orientation-explicit.html?315      image-orientation-ref.html?0
+fuzzy(1,1) == image-orientation-explicit.html?315      image-orientation-ref.html?0
 fuzzy(1,1) == image-orientation-explicit.html?345      image-orientation-ref.html?0
 
 # Tests for image-orientation used on generated content:
 fuzzy(1,1) == image-orientation-generated-content.html?from-image image-orientation-generated-content-ref.html?270&flip
 fuzzy(1,1) == image-orientation-generated-content.html?0          image-orientation-generated-content-ref.html?0
 fuzzy(1,1) == image-orientation-generated-content.html?90         image-orientation-generated-content-ref.html?90
 fuzzy(1,1) == image-orientation-generated-content.html?180        image-orientation-generated-content-ref.html?180
 fuzzy(1,1) == image-orientation-generated-content.html?270        image-orientation-generated-content-ref.html?270

--- a/layout/style/ServoBindings.cpp
+++ b/layout/style/ServoBindings.cpp
@@ -1307,20 +1307,20 @@ void
 Gecko_CopyAlternateValuesFrom(nsFont* aDest, const nsFont* aSrc)
 {
   aDest->alternateValues.Clear();
   aDest->alternateValues.AppendElements(aSrc->alternateValues);
 }
 
 void
 Gecko_SetImageOrientation(nsStyleVisibility* aVisibility,
-                          double aRadians, bool aFlip)
+                          uint8_t aOrientation, bool aFlip)
 {
   aVisibility->mImageOrientation =
-    nsStyleImageOrientation::CreateAsAngleAndFlip(aRadians, aFlip);
+    nsStyleImageOrientation::CreateAsOrientationAndFlip(aOrientation, aFlip);
 }
 
 void
 Gecko_SetImageOrientationAsFromImage(nsStyleVisibility* aVisibility)
 {
   aVisibility->mImageOrientation = nsStyleImageOrientation::CreateAsFromImage();
 }
 

--- a/layout/style/ServoBindings.h
+++ b/layout/style/ServoBindings.h
@@ -280,17 +280,17 @@ void Gecko_nsFont_Destroy(nsFont* dst);
 
 // Font variant alternates
 void Gecko_ClearAlternateValues(nsFont* font, size_t length);
 void Gecko_AppendAlternateValues(nsFont* font, uint32_t alternate_name, nsIAtom* atom);
 void Gecko_CopyAlternateValuesFrom(nsFont* dest, const nsFont* src);
 
 // Visibility style
 void Gecko_SetImageOrientation(nsStyleVisibility* aVisibility,
-                               double aRadians,
+                               uint8_t aOrientation,
                                bool aFlip);
 void Gecko_SetImageOrientationAsFromImage(nsStyleVisibility* aVisibility);
 void Gecko_CopyImageOrientationFrom(nsStyleVisibility* aDst,
                                     const nsStyleVisibility* aSrc);
 
 // Counter style.
 // This function takes an already addrefed nsIAtom
 void Gecko_SetCounterStyleToName(mozilla::CounterStylePtr* ptr, nsIAtom* name,

--- a/layout/style/nsStyleStruct.h
+++ b/layout/style/nsStyleStruct.h
@@ -2042,16 +2042,25 @@ struct nsStyleImageOrientation
     // Add a bit for 'flip' if needed.
     if (aFlip) {
       orientation |= FLIP_MASK;
     }
 
     return nsStyleImageOrientation(orientation);
   }
 
+  static nsStyleImageOrientation CreateAsOrientationAndFlip(uint8_t aOrientation,
+                                                            bool aFlip) {
+    MOZ_ASSERT(aOrientation <= ANGLE_270);
+    if (aFlip) {
+      aOrientation |= FLIP_MASK;
+    }
+    return nsStyleImageOrientation(aOrientation);
+  }
+
   static nsStyleImageOrientation CreateAsFlip() {
     return nsStyleImageOrientation(FLIP_MASK);
   }
 
   static nsStyleImageOrientation CreateAsFromImage() {
     return nsStyleImageOrientation(FROM_IMAGE_MASK);
   }